Speedometer reading incorrectly

[Cortina1975 28]

Happy Easter everyone,

 

I did a type 9 swap on my 1600 Cortina. It's always annoyed me that the speedometer now reads too slow.

 

Can I change the drive gear on the box for the one  fitted to the 4 speed ?. It's 30mm diameter but the one on the Burton's catalogue for the type 9 is 25mm and nla. 

 

Think I had an  E type box but not quite sure.

 

It has 24 teeth. Or does anyone know where i can get a type 9 gear with 24 teeth ?

 

Thanks for any replies :)

 

 

 

 

 

 

[Tigdlo 26]

Ford speedo gears can be a bit of a ballache!

The problem is that the drive gear, on the gearbox tailshaft of your T9 box, might have a different number of teeth from that of your old box.

The simplest way would be to count the teeth on the T9 box nylon driven gear, and calculate what you actually require. 
Incidentally, I don’t think that a 1.6 would normally be fitted with a type E box as standard. I could well be wrong, but I’m sure that they were only used in the 2.0 cars.

I hope that this helps!

[sheffieldcortinacentre 595]

No the 1.3/1.6  Speedo gear wont fit the type 9.

The one you need is from the 1.6 5 speed Capri unfortunately I don't have any details on number of teeth or colour of cog..

Only other way is to remove Speedo & reset needle approx 5 mph below zero when at rest this will then read roughly right ( the mileometer will still read wrong).

The 2.0 one ( for 3.75:1 diff) & the 2.3 ( for the 3.44:1 diff ) are a straight swap just remove bung in tail housing  & poke the gear out).

 

 

Edited April 1 by sheffieldcortinacentre

[Cortina1975 28]

On 4/1/2024 at 4:37 PM, Tigdlo said:

Ford speedo gears can be a bit of a ballache!

The problem is that the drive gear, on the gearbox tailshaft of your T9 box, might have a different number of teeth from that of your old box.

The simplest way would be to count the teeth on the T9 box nylon driven gear, and calculate what you actually require. 
Incidentally, I don’t think that a 1.6 would normally be fitted with a type E box as standard. I could well be wrong, but I’m sure that they were only used in the 2.0 cars.

I hope that this helps!

Thanks Tig.  Looks like my speedometer gear is too big to fit the Type 9...not sure what type of box 1600's had but it cant be the E.

Looks like I have 22T in the type 9 so I guess I need a more teeth to correct the speedo?

[Cortina1975 28]

On 4/1/2024 at 6:59 PM, sheffieldcortinacentre said:

No the 1.3/1.6  Speedo gear wont fit the type 9.

The one you need is from the 1.6 5 speed Capri unfortunately I don't have any details on number of teeth or colour of cog..

Only other way is to remove Speedo & reset needle approx 5 mph below zero when at rest this will then read roughly right ( the mileometer will still read wrong).

The 2.0 one ( for 3.75:1 diff) & the 2.3 ( for the 3.44:1 diff ) are a straight swap just remove bung in tail housing  & poke the gear out).

 

 

Thanks Dr Craig. I might try bending the needle if the cog swap doesn't work. Think my box came out of a 1.8 Sierra ...not sure which diff ratio that would have had?

[Tigdlo 26]

2 hours ago, Cortina1975 said:

Thanks Tig.  Looks like my speedometer gear is too big to fit the Type 9...not sure what type of box 1600's had but it cant be the E.

Looks like I have 22T in the type 9 so I guess I need a more teeth to correct the speedo?

No, you’d need fewer teeth to drive the speedo faster

[Cortina1975 28]

11 hours ago, Tigdlo said:

No, you’d need fewer teeth to drive the speedo faster

 

Hi Tigdlo,

 

Got me thinking so  I was doing some reading that to increase the ratio of a worm drive fewer teeth on the cog are needed. 

I'm wondering if my speedo is faulty and should be reading too fast with the 22T  ..why cant anything be straightforward lol . At the moment it reads about 40mph when doing 50 etc. 

 

I found this chart online that suggests higher ratios need more teeth.. i guess  the prop is spinning faster so the drive needs to slow down...could be completely wrong !

[sheffieldcortinacentre 595]

All I know is that there's 2 types/size of box & you can't swap the Speedo drive between them.

[Tigdlo 26]

2 hours ago, sheffieldcortinacentre said:

All I know is that there's 2 types/size of box & you can't swap the Speedo drive between them.

I think that there are three types of box, if you include the MT75. I’m pretty sure that the speedo gears in those are different again!

The good thing about Ford cable driven speedos is that they all operate at 1000 cable turns per mile, or so I believe.

[sheffieldcortinacentre 595]

Yes  I was referring to the single rail box in 4 or 5 speed flavour. 

The MT 75 shares no parts with the earlier type box.

But the Speedo & clutch cables will connect to them.

& the larger spline clutch is the same.

[sierra3dr 49]

https://www.bearingkits.co.uk/TYPE-9-GEARBOX-SPEEDO-DRIVE-GEAR-24-TEETH/809.htm#gsc.tab=0